qemu-e2k/linux-user/microblaze/cpu_loop.c
Peter Maydell b10089a14c linux-user: Don't call gdb_handlesig() before queue_signal()
The CPU main-loop routines for linux-user generally
call gdb_handlesig() when they're about to queue a
SIGTRAP signal. This is wrong, because queue_signal()
will cause us to pend a signal, and process_pending_signals()
will then call gdb_handlesig() itself. So the effect is that
we notify gdb of the SIGTRAP, and then if gdb says "OK,
continue with signal X" we will incorrectly notify
gdb of the signal X as well. We don't do this double-notify
for anything else, only SIGTRAP.

Remove this unnecessary and incorrect code from all
the targets except for nios2 (whose main loop is
doing something different and broken, and will be handled
in a separate patch).

This bug only manifests if the user responds to the reported
SIGTRAP using "signal SIGFOO" rather than "continue"; since
the latter is the overwhelmingly common thing to do after a
breakpoint most people won't have hit this.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20181019174958.26616-2-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2018-11-12 15:48:00 +01:00

169 lines
5.9 KiB
C

/*
* qemu user cpu loop
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu.h"
#include "cpu_loop-common.h"
void cpu_loop(CPUMBState *env)
{
CPUState *cs = CPU(mb_env_get_cpu(env));
int trapnr, ret;
target_siginfo_t info;
while (1) {
cpu_exec_start(cs);
trapnr = cpu_exec(cs);
cpu_exec_end(cs);
process_queued_cpu_work(cs);
switch (trapnr) {
case 0xaa:
{
info.si_signo = TARGET_SIGSEGV;
info.si_errno = 0;
/* XXX: check env->error_code */
info.si_code = TARGET_SEGV_MAPERR;
info._sifields._sigfault._addr = 0;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
}
break;
case EXCP_INTERRUPT:
/* just indicate that signals should be handled asap */
break;
case EXCP_BREAK:
/* Return address is 4 bytes after the call. */
env->regs[14] += 4;
env->sregs[SR_PC] = env->regs[14];
ret = do_syscall(env,
env->regs[12],
env->regs[5],
env->regs[6],
env->regs[7],
env->regs[8],
env->regs[9],
env->regs[10],
0, 0);
if (ret == -TARGET_ERESTARTSYS) {
/* Wind back to before the syscall. */
env->sregs[SR_PC] -= 4;
} else if (ret != -TARGET_QEMU_ESIGRETURN) {
env->regs[3] = ret;
}
/* All syscall exits result in guest r14 being equal to the
* PC we return to, because the kernel syscall exit "rtbd" does
* this. (This is true even for sigreturn(); note that r14 is
* not a userspace-usable register, as the kernel may clobber it
* at any point.)
*/
env->regs[14] = env->sregs[SR_PC];
break;
case EXCP_HW_EXCP:
env->regs[17] = env->sregs[SR_PC] + 4;
if (env->iflags & D_FLAG) {
env->sregs[SR_ESR] |= 1 << 12;
env->sregs[SR_PC] -= 4;
/* FIXME: if branch was immed, replay the imm as well. */
}
env->iflags &= ~(IMM_FLAG | D_FLAG);
switch (env->sregs[SR_ESR] & 31) {
case ESR_EC_DIVZERO:
info.si_signo = TARGET_SIGFPE;
info.si_errno = 0;
info.si_code = TARGET_FPE_FLTDIV;
info._sifields._sigfault._addr = 0;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case ESR_EC_FPU:
info.si_signo = TARGET_SIGFPE;
info.si_errno = 0;
if (env->sregs[SR_FSR] & FSR_IO) {
info.si_code = TARGET_FPE_FLTINV;
}
if (env->sregs[SR_FSR] & FSR_DZ) {
info.si_code = TARGET_FPE_FLTDIV;
}
info._sifields._sigfault._addr = 0;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
default:
fprintf(stderr, "Unhandled hw-exception: 0x%" PRIx64 "\n",
env->sregs[SR_ESR] & ESR_EC_MASK);
cpu_dump_state(cs, stderr, fprintf, 0);
exit(EXIT_FAILURE);
break;
}
break;
case EXCP_DEBUG:
info.si_signo = TARGET_SIGTRAP;
info.si_errno = 0;
info.si_code = TARGET_TRAP_BRKPT;
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case EXCP_ATOMIC:
cpu_exec_step_atomic(cs);
break;
default:
fprintf(stderr, "Unhandled trap: 0x%x\n", trapnr);
cpu_dump_state(cs, stderr, fprintf, 0);
exit(EXIT_FAILURE);
}
process_pending_signals (env);
}
}
void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
{
env->regs[0] = regs->r0;
env->regs[1] = regs->r1;
env->regs[2] = regs->r2;
env->regs[3] = regs->r3;
env->regs[4] = regs->r4;
env->regs[5] = regs->r5;
env->regs[6] = regs->r6;
env->regs[7] = regs->r7;
env->regs[8] = regs->r8;
env->regs[9] = regs->r9;
env->regs[10] = regs->r10;
env->regs[11] = regs->r11;
env->regs[12] = regs->r12;
env->regs[13] = regs->r13;
env->regs[14] = regs->r14;
env->regs[15] = regs->r15;
env->regs[16] = regs->r16;
env->regs[17] = regs->r17;
env->regs[18] = regs->r18;
env->regs[19] = regs->r19;
env->regs[20] = regs->r20;
env->regs[21] = regs->r21;
env->regs[22] = regs->r22;
env->regs[23] = regs->r23;
env->regs[24] = regs->r24;
env->regs[25] = regs->r25;
env->regs[26] = regs->r26;
env->regs[27] = regs->r27;
env->regs[28] = regs->r28;
env->regs[29] = regs->r29;
env->regs[30] = regs->r30;
env->regs[31] = regs->r31;
env->sregs[SR_PC] = regs->pc;
}